Currently, clear dietary recommendations for pregnant and breastfeeding mothers are lacking regarding allergy prevention in allergic or non-allergic families, although there is a great need to have firm evidence-based guidelines to advise families. Human studies to investigate the effect of strict food allergen avoidance, such as peanut, during pregnancy and lactation on the infant's risk towards development of food allergy are difficult to perform and potentially unethical. Animal studies have suggested that tolerance is induced by perinatal feeding of antigen. These studies have assessed naive mothers to assess risk of OVA-triggered asthma and peanut-allergic mothers to assess risk of peanut allergy. The novelty of this proposal is to assess mothers who are tolerant to the food in question, which is relevant to most of the humans. In the current proposal, we therefore aim to address the effect of feeding peanut during lactation on the offspring's predisposition toward allergic sensitization using an animal model of peanut allergy. We also aim to determine the potential mechanism of oral tolerance development provided via maternal milk. These animal studies will establish biological basis for maternal and infant feeding guidelines in order to address the increasing frequency of food allergies. Once basic mechanisms of this protection against or increased risk towards food allergy have been detected, the future studies could be performed in a human cohort of mothers who choose or do not choose to adhere to avoidance diets. My immediate goal is to obtain intensive training in immunobiology and experimental models of food allergy to add to my skills in mucosal immunology and maternal-infant interface of immunity. As a long-term goal, I strive to pursue a career in translational research to utilize both my skills in basic research as well as patient care and with that would like to develop into an independent research investigator. The proposed career development activities are a combination of coursework and informal training that will strengthen my knowledge and research skills in immunobiology applied to oral tolerance development. The Pediatric Allergy and Immunology Division and The Immunology Institute Mount Sinai School of Medicine provide an excellent forum for these activities, which include informal interactions with the faculty as well as formal courses in immunobiology and biostatistics, journal clubs, seminars and work-in- progress presentations, as well as training in responsible conduct of research. NARRATIVE: This research aims to solve a health concern of great public interest: should breastfeeding mothers avoid or eat potential food allergens in order to avoid development of food allergy in their children.